Hardware, interfaces, and keyboard magic.
MIDI – Musical Instrument Digital Interface. Midi is a communication language between computers and things with computer chips e.g. Matt can have his keyboard talk to his laptop. You can store all sorts of sound in different software programs on your laptop, then if you travel (like Matt) you only need to take your laptop (and a few other things) to reproduce the sounds you want instead of hoping the destination has the right sounds there.
Midi opens up a whole world of sound.